---
product_id: 51055796
title: "Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown)"
brand: "noctua"
price: "€ 27.17"
currency: EUR
in_stock: true
reviews_count: 9
category: "Noctua"
url: https://www.desertcart.ie/products/51055796-noctua-nf-a4x20-pwm-premium-quiet-fan-4-pin-40x20mm
store_origin: IE
region: Ireland
---

# 150,000+ hours MTTF 5000 RPM max speed Ultra-quiet 14.9 dB(A) Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown)

**Brand:** noctua
**Price:** € 27.17
**Availability:** ✅ In Stock

## Summary

> 🌀 Stay cool, stay quiet — the pro’s choice for stealthy performance.

## Quick Answers

- **What is this?** Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown) by noctua
- **How much does it cost?** € 27.17 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/51055796-noctua-nf-a4x20-pwm-premium-quiet-fan-4-pin-40x20mm)

## Best For

- noctua enthusiasts

## Why This Product

- Trusted noctua brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Compact Yet Mighty:** Slim 40x40x20mm size fits tight spaces like 1U servers and NAS devices without compromise.
- • **Whisper-Quiet Power:** Experience near-silent airflow at max 14.9 dB(A), perfect for noise-sensitive workspaces.
- • **OmniJoin Adaptability:** Innovative OmniJoin connectors let you integrate the fan with any custom power setup—no cable stripping needed.
- • **Precision PWM Control:** 4-pin PWM enables smart automatic speed adjustments for optimal cooling and energy efficiency.
- • **Vibration-Free Mounting:** Includes anti-vibration mounts and premium accessories for seamless, rattle-free installation.

## Overview

The Noctua NF-A4x20 PWM is a premium 40x40x20mm quiet fan designed for professional-grade cooling in compact devices like 1U servers and NAS units. Featuring a max speed of 5000 RPM with ultra-low noise levels of 14.9 dB(A), advanced aerodynamic design, and a 4-pin PWM interface for smart speed control, it delivers efficient, whisper-quiet airflow. The fan comes with a comprehensive accessory kit including anti-vibration mounts, extension cables, and the unique OmniJoin adaptor set for effortless custom installations, backed by a remarkable 150,000+ hour MTTF for long-lasting reliability.

## Description

Premium quiet 40x20mm fan with advanced aerodynamic design for superior cooling performance. Features 4-pin PWM control for automatic speed adjustment.

Review: Top-notch-quality quiet fan and _unbelievably comprehensive_ accessory kit, worth the price of the kit alone! - I bought this fan to replace the noisy one included in an old HDD IDE rack I need to use (the cheap supplied fan has become unbearably noisy due to dust after just a few months of everyday use, unfortunately...). This was the first time I bought a Noctua fan, even if I knew this is one of the highest-quality brands of silent fans, and although some people might think this specific kit is overpriced for a small 40x40x10mm fan, I can assure you that the packaging and the accessories included in it are worth the price of the product alone! The fan itself is almost completely inaudible outside of a case, especially when used at reduced speed, which can be obtained by using the clever low-noise adaptor: a small, inconspicuous cable extension, which goes between the fan connecting cable and the power source connector, and lowers the rotating speed from 4500 to 3700 rpm; by the way, the air flow produced even at reduced speed seems considerable anyway, in my opinion. But the most amazing aspect of this product are the supplied accessories included in this gorgeous kit: apart from some typical, high-quality metal screws, you get professional silicon pins, which can be used to mount the fan screwlessly in order to reduce vibrations, an extension cable, an adaptor cable to convert from 3 to 2 power pins, and the most wonderful adapter of them all: the incredible OmniJoin adaptor set, which includes an extension cable ending with 2 truncated red/black power wires, and four _amazing_ "crimp-like" connectors, which allow you to join the truncated power wires to any other corresponding wires coming from _any_ appropriate fan power source inside the PC, _without even having to remove the insulation from the cables_ (!). Basically, in case you want to attach this fan to any "custom" connecting cable with a connector that does not fit any of the included adaptors, you can just cut the connector off of your available custom power cable, and join the resulting truncated black/red wires with the corresponding truncated ones from the Noctua OmniJoin adapter, "crimping" (pressing) the red/black power wires together using 2 of the 4 omnijoint proprietary connectors with flat-nose pliers (not included). If this sounds complicated, actually I assure you it is not, and everything is explained in extremely clear instructions with detailed figures included in the kit, of course. It is a _very_ clever and professional alternative to just "splicing" power cables together with insulating tape, in my opinion! In the future, I will definitely try more Noctua products like this one, in case I need to attach a fan to a custom power cable, hoping they will work with no problems... (Please note that I have _not_ tried the omnijoint connectors, since I do not need them for my specific connector, luckily.) So, all things considered, in my opinion you _definitely_ get what you pay with this amazing product, and I just hope the fan will last for a long time!
Review: Quieter than a mouses fart!!! - Bought an old 4 bay 1U rackmount NAS from eb** and was shocked how noisy it was. 60+db while building a raid array. So thought not happening and went looking for silent fans, found these and read the reviews and being a Scotsman I was like seriously? for a wee fan like that? and there were 3 system fans and 1 power supply fan. I was aboot greetin. Bought the 4 fans and proceeded to swap them out taking measurements along the way. After replacing the 3 system fans the noise level dropped to a low of 21db and peak of 25db system temp 1degree lower CPU temp 1 degree higher. I then swapped the power supply fan and set the system to rebuilding a raid volume, which is possibly the most intensive thing a NAS is going to do and it is quite happily purring along at a peak of 18 db with a system temp 2 degrees lower and a CPU temp 1 degree higher than factory fitted fans. I should mention that I am using the low noise adaptor cables that come supplied in the fan kit for the 3 system fans. The kit is well supplied with everything you need and gives you options aplenty for extensions and fitting methods. The quality seems to be superb and longevity is backed by their guarantee. I will be buying these fans exclusively from now on and upgrading all fans in my servers. The only nark I would have is the colour! My god it's awful lets have some bright colourful options yellow/black red/black etc, something to indicate that it's a premium high performance fan. Lookswise it definitely needs some cool. Other wise very happy if not skint wee laddie but well worth it.

## Features

- Premium quiet fan, 40x40x20 mm, 12V, 4-pin PWM, max. 5000 RPM, max. 14.9 dB(A), >150,000 h MTTF
- Award-winning A-series design with Flow Acceleration Channels and Advanced Acoustic Optimisation frame for superior quiet cooling performance
- 40x20mm size ideal for 1U servers or replacing fans in network and storage equipment (routers, switches, NAS etc.) or other devices such as DVRs
- 4-pin PWM version for automatic speed control via 4-pin PWM fan headers, 5000rpm maximum speed (4400rpm with supplied Low-Noise Adaptor)
- Includes anti-vibration mounts, fan screws, extension cable, y-cable and OmniJoin adaptor set for connecting the fan to proprietary fan headers

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07125KWG1 |
| Are Batteries Included | No |
| Best Sellers Rank | 2,576 in Computers & Accessories ( See Top 100 in Computers & Accessories ) 2 in Thermal Management Products 21 in Fans & Cooling |
| Brand | Noctua |
| Colour | Brown |
| Customer Reviews | 4.8 4.8 out of 5 stars (20,071) |
| Date First Available | 3 Jun. 2017 |
| Guaranteed software updates until | unknown |
| Item Weight | 1 g |
| Item model number | NF-A4x20 PWM |
| Manufacturer | Noctua |
| Product Dimensions | 4 x 4 x 2 cm; 1 g |
| Series | NF-A4x20 PWM |
| Voltage | 12 Volts |

## Product Details

- **Air flow capacity:** 9.4 Cubic Metres Per Hour
- **Brand:** Noctua
- **Compatible devices:** Desktop, Laptop
- **Cooling method:** forced air
- **Material:** Fibre-glass reinforced PBT
- **Maximum rotational speed:** 5000 RPM
- **Noise level:** 14.9 Decibels
- **Power connector type:** 4-Pin
- **Product dimensions:** 40L x 40W x 20H millimetres
- **Voltage:** 12 Volts

## Images

![Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown) - Image 1](https://m.media-amazon.com/images/I/71lyRpVR4OL.jpg)

## Questions & Answers

**Q: How can I use this fan with a 2 pin connection. I’ve just received it only to find my connection is 2 pin. Doh!**
A: Black is (-), red is (+) and yellow is just the probe. You disconnect/cut the yellow one and you have two active wires.

**Q: You replaced Hikvision nvr fan with Noc 40x20. What voltage did u use 12 or 5?**
A: This Noctua fan is rated 5V and this is the voltage to use.

**Q: has anyone tried this in a dan a4 case as a top fan? And would it be worth doing?**
A: I don't know where it would fit at the top of the A4, as the riser cables and psu cable take up the space, there might just be enough space on the GPU side. I have this fan zip-tied to the CPU side panel.

**Q: Good day, when will this item be back in stock again?**
A: it is https://www.amazon.co.uk/gp/offer-listing/B009NQLT0M/ref=dp_olp_new_mbc?ie=UTF8&condition=new

## Customer Reviews

### ⭐⭐⭐⭐⭐ Top-notch-quality quiet fan and _unbelievably comprehensive_ accessory kit, worth the price of the kit alone!
*by V***R on 16 November 2012*

I bought this fan to replace the noisy one included in an old HDD IDE rack I need to use (the cheap supplied fan has become unbearably noisy due to dust after just a few months of everyday use, unfortunately...). This was the first time I bought a Noctua fan, even if I knew this is one of the highest-quality brands of silent fans, and although some people might think this specific kit is overpriced for a small 40x40x10mm fan, I can assure you that the packaging and the accessories included in it are worth the price of the product alone! The fan itself is almost completely inaudible outside of a case, especially when used at reduced speed, which can be obtained by using the clever low-noise adaptor: a small, inconspicuous cable extension, which goes between the fan connecting cable and the power source connector, and lowers the rotating speed from 4500 to 3700 rpm; by the way, the air flow produced even at reduced speed seems considerable anyway, in my opinion. But the most amazing aspect of this product are the supplied accessories included in this gorgeous kit: apart from some typical, high-quality metal screws, you get professional silicon pins, which can be used to mount the fan screwlessly in order to reduce vibrations, an extension cable, an adaptor cable to convert from 3 to 2 power pins, and the most wonderful adapter of them all: the incredible OmniJoin adaptor set, which includes an extension cable ending with 2 truncated red/black power wires, and four _amazing_ "crimp-like" connectors, which allow you to join the truncated power wires to any other corresponding wires coming from _any_ appropriate fan power source inside the PC, _without even having to remove the insulation from the cables_ (!). Basically, in case you want to attach this fan to any "custom" connecting cable with a connector that does not fit any of the included adaptors, you can just cut the connector off of your available custom power cable, and join the resulting truncated black/red wires with the corresponding truncated ones from the Noctua OmniJoin adapter, "crimping" (pressing) the red/black power wires together using 2 of the 4 omnijoint proprietary connectors with flat-nose pliers (not included). If this sounds complicated, actually I assure you it is not, and everything is explained in extremely clear instructions with detailed figures included in the kit, of course. It is a _very_ clever and professional alternative to just "splicing" power cables together with insulating tape, in my opinion! In the future, I will definitely try more Noctua products like this one, in case I need to attach a fan to a custom power cable, hoping they will work with no problems... (Please note that I have _not_ tried the omnijoint connectors, since I do not need them for my specific connector, luckily.) So, all things considered, in my opinion you _definitely_ get what you pay with this amazing product, and I just hope the fan will last for a long time!

### ⭐⭐⭐⭐⭐ Quieter than a mouses fart!!!
*by J***. on 4 May 2025*

Bought an old 4 bay 1U rackmount NAS from eb** and was shocked how noisy it was. 60+db while building a raid array. So thought not happening and went looking for silent fans, found these and read the reviews and being a Scotsman I was like seriously? for a wee fan like that? and there were 3 system fans and 1 power supply fan. I was aboot greetin. Bought the 4 fans and proceeded to swap them out taking measurements along the way. After replacing the 3 system fans the noise level dropped to a low of 21db and peak of 25db system temp 1degree lower CPU temp 1 degree higher. I then swapped the power supply fan and set the system to rebuilding a raid volume, which is possibly the most intensive thing a NAS is going to do and it is quite happily purring along at a peak of 18 db with a system temp 2 degrees lower and a CPU temp 1 degree higher than factory fitted fans. I should mention that I am using the low noise adaptor cables that come supplied in the fan kit for the 3 system fans. The kit is well supplied with everything you need and gives you options aplenty for extensions and fitting methods. The quality seems to be superb and longevity is backed by their guarantee. I will be buying these fans exclusively from now on and upgrading all fans in my servers. The only nark I would have is the colour! My god it's awful lets have some bright colourful options yellow/black red/black etc, something to indicate that it's a premium high performance fan. Lookswise it definitely needs some cool. Other wise very happy if not skint wee laddie but well worth it.

### ⭐⭐⭐⭐⭐ SILENT!
*by A***H on 6 January 2026*

Epic little fan. Silent at full speed can’t hear it at all. Got it cooling my vrm heatsink. May get another!

## Frequently Bought Together

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- Noctua NF-A6x25 PWM, Premium Quiet Fan, 4-Pin (60mm, Brown)
- Noctua NF-A8 PWM, Premium Quiet Fan, 4-Pin (80mm, Brown)

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-02-10*